1. Technical Field of the Invention
The present invention relates to a plasma processing apparatus for performing various surface processing such as etching, ashing, deposition, surface reforming and surface cleaning of semiconductor substrates, display substrates, multi-chip modules (MCM), printed circuit boards, and the like by means of applying plasma discharge.
2. Background Art
With regard to etching, ashing, deposition, surface reforming and surface cleaning of semiconductor substrates and the like according to conventional LSI manufacturing processes, various types of plasma processing apparatuses are being widely used which process substrates by generating plasma under a reduced pressure environment.
In these types of plasma processing apparatuses, a load-lock chamber is provided adjacent to the processing chamber in which the plasma processing is performed, and the substrates are transported through this load-lock chamber. In this case, an opening is provided between the processing chamber and the load-lock chamber for transporting substrates. During processing, this opening is hermetically sealed by a gate element, referred to as a "gate valve", and during transport, substrates are moved in and out of this opening.
However, with conventional plasma processing apparatuses, one load-lock chamber is normally provided for each processing chamber. As a result, problems arise in that the number of substrates that are processed per unit time, i.e., the throughput, is small. Consequently, a plasma processing apparatus with a large throughput is highly desirable.